Screw-propeller.



FERNAND BnoUissoUsn, or Linen, BELGIUM.

scnnwnornnnna SpecicationfofLe-tters Patent.

Patented Apr. 2, 1912.

Application led- J'uly 11, 1910. Serial No.` 571,441."

To all 'it concern: i

Be it known that I, FnRNANn BRoUssoUsn,

i a subj ect of the Kingdom of Belgium, residing at 13 Rue des Armuriers, in Liege, Belgium, have inventedacertain new and useful Improvements in 'Screw-Propellers; and I' do hereby declare the following to be a full,

clear, and exact description of the invention, such as vwill enable 'others skilled in the art same, reference being had to the accompanying drawings, and to letters or figures of reference markedthereon, which form a part of this specification.

My present invention relates to an im@ provement in screw'pro'pellers. l

In my present improved device I provide 'an arrangement of a plurality of auxiliary or directing blades in combination with the main blades of said screw propeller and which are subsidiary to the same, and being integrally mounted upon the hub of the main blades turn simultaneously with the Same.

. The main feature of this invention lies in the disposition'of these auxiliary blades upon the boss and their respective pitches.

By my improved device and during the rotation of the propeller a progressive de tlection ofthe fluid' stream lines is secured,-

the eddies and dead water produced by the ordinary screw propeller being ths avoided. Owing to the improved structure in my device thepropelling efficiency is increased and abetter attacking actionof the blades on the watertakes place.

Fi 2 a section on the line A-B, Fig. 2.

n Fig.v 1 is shown a propeller in its entirety, composed of the main blades 1 and the auxiliary or directing blades 2, and 3, integrally attached to the boss-ofthe main propellers and shows the respective advance' of the attacking edges', the arrow 5 showing the direction of rotation.

of attack, vcorresponding to the pitches or angles T and respectively-"are smaller than the angle `of attacker ofthe main blades 1,

vFigure 1 is a front view of the propeller.

while they decrease successively in such a manner that there are formed the various angles cz, and Y. These blades are also characterized by their disposition on the boss blades 1. to which 1t appertainsto make and use the -in a successive fashion by the whole group of blades 3, 2, and 1.-. The dead water and all eddies which would be formed therein by the use 'of blades 1 alone are by this vmethod avoided, witha lconsequent increase of the propelling eiiiciency.

yIt is not to be inferred that my new arrangement simplyconsists of a group of propeller blades ofdil'erent` pitches integrally arranged on one hub or boss, for the conditions of efficiency of the above described' impro-vement lie in the progressive arrangement -of the blade edges and the relative positions of the entering edges of the ,preceding blades and`the location of the exit edges of the blades succeeding them.

Il have found that to obtain the best arrangement the entrance edges of each blade should be in advance of'and overlap the exit edges v and y of the succeeding blades as in Fig. 2, where the entrance portion ofthe blade 2 is shown positioned in advance of the exit portionv of blade l when considered in a plane parallel to line `M-N.

1I-Iaving thus described my invention, I c aim:

- A propeller having av pluralityof heli-v coidal elements consisting-of a mainblade. andv a plurality of directing blades, said directing blades arranged with their entrance edges en eckelon behind said main blade, the

pitchesof said directing blades being. less than that of said mainl blade and decreasing progressively from one another rearward.Y In testimony vthat I claim the 'foregoing as my invention, I have signedmi;r name in plsence'of two subscribing witnesses; FERNAND BROUSSOUSE. v

Witnesses:`

LEONARD'LEVA, .ALEX LAILEMUND. 

